1. Field of the Invention
The present invention relates to a sealing device, particularly, relates to a sealing device preferable when used for sealing an interval between an outer ring and an inner ring of a rolling bearing rotatably supporting a main spindle of a machine tool.
Further, the invention relates to a rolling bearing apparatus including two race way members, a rolling element and a sealing device.
2. Related Art
In a background art, as a rolling bearing apparatus, there is a rolling bearing apparatus for a machine tool described in JP-A-2006-064106.
The rolling bearing apparatus rotatably supports a main spindle of a machine tool. The rolling bearing apparatus includes an outer ring, an inner ring, a plurality of rolling elements, and seal members of covering openings on both sides in an axial direction between the outer ring and the inner ring.
Whereas one end portion on an outer side in a diameter direction of a seal member is fixed to the outer ring, other end portion on an inner side in the diameter direction of the seal member is disposed relative to an outer peripheral face of the inner ring to be spaced apart from each other by an interval therebetween in the diameter direction. The other end portion of the seal member and the outer peripheral face of the inner ring constitute a labyrinth seal.
A main spindle of a machine tool is rotated at a high rotational speed of about several tens of thousands min−1. According to the rolling bearing apparatus of the background art, by constituting the labyrinth seal, running cost is made to be small such that when the inner ring is rotated relative to the outer ring, a torque which is to be generated when the other end portion of the sealing device were brought into sliding contact with the inner ring is prevented from being generated.